Well, it works...almost. I get a lot of stuck notes and incorrect notes or notes that don't sound at all using an M-Audio 49 keyboard. I'm hoping that my particular BassBoy is somehow defective. I'd hate to think this was a 'normal' device. Too bad, since it is pretty cheap. Not worth returning for my money back since shipping was US$25.

Anybody have better success than me?_________________Synth DIY since 1977!

Interesting. Do you have access to a different keyboard? Or scoped the MIDI logic output before it goes into the uC? I've heard of more than one odd MIDI thing happening due to grounding that shouldn't be there. I'm wondering why it costs $25 to ship it..._________________FPGA, dsPIC and Fatman Synth Stuff

Time flies like a banana.Fruit flies when you're having fun.BTW, Do these genes make my ass look fat?corruptio optimi pessima

OK, I switched keyboards and it worked just fine. The M-Audio 49 is my go-to keyboard for testing and seems to play all my other midi stuff just fine. The other keyboard that did work was a Doepfer MKE unit. Hmmmm. It's bad enough I have a project queue...now I have to add diagnostics to a module and keyboard! _________________Synth DIY since 1977!

Cool, that would mean that there's likely nothing wrong with the bass machine itself.

I had another friend with a similar problem which turned out to be an inexpensive USB to MIDI adapter that had a funky ground connection which caused something like what you described. Maybe check how the "bad" keyboard is wired internally? What's even more frustrating is I'll bet you can find equipment that will work just fine with that keyboard.

And as TheProf wrote, cables can be a problem as well. (mine are mostly home-made).

Heh, and Dan, why do you think you should be excluded from the herd of people (myself included) that have such queues? _________________FPGA, dsPIC and Fatman Synth Stuff

Time flies like a banana.Fruit flies when you're having fun.BTW, Do these genes make my ass look fat?corruptio optimi pessima

Scott, well it's not as cool as just about everything you're working on, but it is cheap and dirty and does make a nice bass voice. The slide/portamento effect can be initiated with legato playing but if you leave a note down, play a second note then release the second note, the first note does not sound again, so it's not as monophonic synth-like as I prefer. I have yet to set up the cc controls for filter, etc. so I can't tell you how those work. Apparently, they are using a "moog" algorithm for the filter...we'll see. They may want to change that to "transistor ladder" to avoid possible trademark issues.

Another possibility is that the opto-isolator pull-up resistor may not optimized. I remember working on TH's Midi to CV-Gate/Trigger unit and having to change the value to get it to work with everything I had. I had similar problems Tom verified the schematic. Maybe it was the same M-Audio kbd? I don't remember, it was a couple years ago.

The unit ships from Serbia. It was fun tracking the shipment thru eastern Europe. Nowhere do they mention they are in Serbia. I wonder if they think there's still bad feelings from the Balkans war? I think there are a lot more issues in the world to worry about now.

I think The Prof is right. Group buy is the way to go. Maybe someone from each country can organize one_________________Synth DIY since 1977!

^ Offtopic: Not really bad feelings from the wars, but Eastern Europe isn't exactly prospering, and there is a general mistrust for EE countries - at least in Western Europe. It's because impoverished EE citizens often emigrate to Western Europe countries, and by 'impoverished EE citizens' I mean mostly gypsies who want to live off social welfare aids and petty crime. Thissort of gypsies. So that's probably why Serbia isn't mentioned anywhere.

I remember 'Sasha', (I'm not sure of he's on here - he does more on MIDIbox), complaining about the endless official paperwork and costs of exporting from Serbia when I helped with his modified x0xb0x project, (he did the panels and modified PCB's, I sorted out a parts bulk buy). I wonder if he's using DHL to cover all that, too? Is Serbia still subject to trade sanctions?, I know it was at one time.

Back to the MIDI problem. If it's a non-optimised opto resistor, (good thinking Dan!), then you'll have to trot out the SMT kit. It's a new product, and it might be he's not that familiar with production spread; a slightly low sensitivity on the opto might hit a limit somewhere if the resistor is sub optimal.

Same goes for the keyboard. The orginal MIDI spec calls for drive from a transistor or TTL open collector output. A lot of more modern devices use a pin of a micro processor, sometimes these can be a bit marginal on current drive. I had a similar problem with a friends portable groovebox, (can't remember the model - could have been a Yamaha). A loop check revealed it wasn't capable of delivering the specified current. With good sensitive optos in The devices he was driving, it worked fine, but failed with a few older units. My solution was to add a small buffer, and use the spare stages in the chip to drive LED's. I do that with some of my home made MIDI gear for another reason, the driver chip is there because it's easy to replace if some kind of bad wiring problem kills it, (this is me playing safe for when equipment goes out live; a CD4049 I can change, a programmed PIC or AVR is another matter), though I may be over worrying about this!

You could check by putting MIDI splitter in line with the M-Audio and seeing if the problem went away. If you haven't got one, there are quite a few designs around - the parts cost is trivial, and they perfboard up easily.

Trade sanctions? Not anymore, I think, but they aren't in the EU, either, which does indeed make shipping costs to pretty much anywhere quite prohibitive, thanks to various customs taxes.

Have you heard about the case when (sometime in the mid-20th century I guess) the customs service of some country took a bunch of perforated cards which contained a computer program for a 'bulk item', so they took a 'sample' from them, as law required them to. Took the debugging team a while to find out why the program didn't work

I've been looking at the midi in circuit here. Is it just me or does that 10K pull up resistor on pin 5 of the CNY17-3 seem a little high? On a 5V circuit, I usually see something in the 1-2K range._________________Synth DIY since 1977!

That's a pullup on an open collector transistor. In my opinion, 10K should work and so should 1K.

I would look at the the collector pin with an Oscope - when the MIDI signal is present, the signal should ideally be a nice rectangular waveform from near 0 volts to near 3.3 volts. If it's sharp/crisp like that, it should work.

That resistor basically sets the gain of the transistor where the higher the resistance the higher the gain, but lower collector current. The circuit receiving that should ideally have a fairly high impedance and should not load it. If it looks sloppy, as in a slow rise or slow fall, you might try other values (such as 2K or 1K) and see if that improves it. Seeing the difference on the Oscope will tell you whether you are improving it.

I don't have a datasheet for that optoisolator - what you need to do is look at the collector current rating. 1K at 3.3v will allow 3.3mA to flow. Make sure that the current allowed by the pullup won't violate max Ic (collector current). If it's below max, it can still work very well - and won't blow the IC._________________FPGA, dsPIC and Fatman Synth Stuff

Time flies like a banana.Fruit flies when you're having fun.BTW, Do these genes make my ass look fat?corruptio optimi pessima

If you look at the schematic, the base of the phototransistor is connected with a 100KOhm
resistor to ground. That improve CNY17-3 speed (rise 5.6uS/fall 3.6us) instead of 6.4uS/123.6uS without resistor.

I'm a bit tied up right now, but the project will be finished eventually.

The idea is this:
it has 12 pots, where 4 pots can be either pot or switch.
it will work as midi merger, recieving notes via midi input, and will send notes together with midi cc values from pots itself to midi output.
Sasha (midibox.org) is completing the sequencing part of xoxbox, and integration of this pot board will be very easy, but can also work as a standalone midi pot control.

IMPORTANT:

Sincere apology to everyone who already bought older version of bassboy

After the ports initialization, the state of the ports cannot be read immediately, so the information about the state of the ports can be wrong. Is it a atxmega bug or problems appeared from production process itself, there is a chance that bassboy doesn't read the state of playing mode & channel mode pins correctly. This can be resolved in following way (this applies only to version SSP 1.0; in newer version a time delay has been added): add a resistor network 10k SIL5 - see picture below.

If you look at the schematic, the base of the phototransistor is connected with a 100KOhm
resistor to ground. That improve CNY17-3 speed (rise 5.6uS/fall 3.6us) instead of 6.4uS/123.6uS without resistor.

I suspect my initial problems were due to my M-Audio keyboard that I used for testing. Bassboy worked quite well with my Doepfer MKE unit. I really like how the fingered portamento (slide) works.

3. Really looking forward to the controller board! This will really make this unit shine. I tried to test it with my Alesis Photon X25 keyboard, but the LCD stopped funtioning and I couldn't program the knobs to correctly control the BassBoy! All I could get was a little filter and volume control.

4.

Quote:

After the ports initialization, the state of the ports cannot be read immediately, so the information about the state of the ports can be wrong.

Thanks for the fix. Looks simple enough, especially since the rest of the unit is already assembled._________________Synth DIY since 1977!

Cynosure:
you may want to propose a group buy for, say Ontario, then the shipping won't be so bad. If you can't handle the buy yourself, maybe someone else could step up?_________________Synth DIY since 1977!

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